HTTP connection issues
Devices can connect to IoT Platform over HTTP. This topic describes common issues and provides solutions.
What do the error codes returned by the server mean during HTTPS device authentication?
For descriptions of the error codes returned during device authentication, see HTTPS connection and communication.
How is the sign parameter in the body generated for HTTPS access authentication?
The sign parameter is calculated using the following method: hmacmd5(deviceSecret,content). For more information, see HTTPS connection and communication.
The server returns "302 Found, The requested resource resides temporarily under a different URI"
Do not access the root directory path directly. Instead, use the full access path that includes the domain name: https://iot-as-http.cn-shanghai.aliyuncs.com/auth
A cross-domain error occurs when an HTTP request is sent from a browser
Alibaba Cloud does not currently support cross-domain HTTP requests from browsers.
Does the HTTP protocol support downstream data transmission?
Neither HTTP nor Constrained Application Protocol (CoAP) supports downstream data transmission. For this functionality, we recommend using Message Queuing Telemetry Transport (MQTT), which supports both upstream and downstream data transmission.